Abstract

We report a microstructural investigation of the epitaxialgrowth of YBa2Cu3O7−x(YBCO)thin films on LaAlO3 (001) substrates using transmission electron microscopy(TEM).Epitaxialfilmsgrow with two distinct modes: cepitaxy(YBCO)single crystal with the c axis normal to the surface) and aepitaxy(YBCO)single crystal with the c axis in the interfacial plane), where cepitaxy is the dominant mode grown in all samples 35–200 nm thick. In 35 nm YBCOfilmsannealed at 850 °C, 97±1% of the surface area is covered by cepitaxy with embedded anisotropica‐epitaxial grains. Quantitative analysis reveals the effect of film thickness and annealing temperature on the density, grain sizes, areal coverages, and anisotropicgrowth of aepitaxy.